The objective of the Structural Core on the Parkin/PINK1/DJ-1 (PPD) complex will be to provide the structural basis for Projects 1 and 2 investigating the PPD complex in humans and drosophila, as well as its modification and regulation by means such as S-nitrosylation, as investigated in Project 3. We will develop expression systems and strategies to obtain a range of single protein constructs and partial complexes of the PPD suitable for structural characterization. In addition, we will extend our efforts toward crystallization of the full-length proteins and the holo PPD-complex, which we have successfully obtained in preliminary experiments. The goal will be to crystallize and structurally characterize all aspects of the PPD by X-ray crystallography, with our findings to be complemented by other in vitro methods in collaboration with Core B (Proteomics Core). Results will directly feed back into the efforts of Projects 1, 2 and 3. We will further attempt to investigate the structure of S-nitrosylated constructs to visualize the direct effect of this modification as evaluated by Project 3. Taken together we will support our biology effort by deciphering details about the regulation and mechanism of the PPD in atomic resolution and thus help explain our findings and obtain new insight. Moreover, this core will not only serve Projects 1, 2, and 3, but also will provide a structural basis for Core E (High-throughput Chemical Library Screening Core) aiding the discovery of lead compounds and their structure based optimization;thus ultimately fostering our effort to develop new drugs for Parkinson's disease (PD) that are designed to interact with PPD components and other PD-related proteins.